/*
 * Copyright 2012 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkPathOpsCubic_DEFINED
#define SkPathOpsCubic_DEFINED

#include "include/core/SkPoint.h"
#include "include/core/SkScalar.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkDebug.h"
#include "include/private/base/SkMalloc.h"
#include "src/base/SkArenaAlloc.h"
#include "src/pathops/SkPathOpsDebug.h"
#include "src/pathops/SkPathOpsPoint.h"
#include "src/pathops/SkPathOpsTCurve.h"

class SkIntersections;
class SkOpGlobalState;
struct SkDConic;
struct SkDCubicPair;
struct SkDLine;
struct SkDQuad;
struct SkDRect;

struct SkDCubic {
    static const int kPointCount = 4;
    static const int kPointLast = kPointCount - 1;
    static const int kMaxIntersections = 9;

    enum SearchAxis { kXAxis, kYAxis };

    bool collapsed() const
    {
        return fPts[0].approximatelyEqual(fPts[1]) && fPts[0].approximatelyEqual(fPts[2]) &&
            fPts[0].approximatelyEqual(fPts[3]);
    }

    bool controlsInside() const
    {
        SkDVector v01 = fPts[0] - fPts[1];
        SkDVector v02 = fPts[0] - fPts[2];
        SkDVector v03 = fPts[0] - fPts[3];
        SkDVector v13 = fPts[1] - fPts[3];
        SkDVector v23 = fPts[2] - fPts[3];
        return v03.dot(v01) > 0 && v03.dot(v02) > 0 && v03.dot(v13) > 0 && v03.dot(v23) > 0;
    }

    static bool IsConic()
    {
        return false;
    }

    const SkDPoint &operator[](int n) const
    {
        SkASSERT(n >= 0 && n < kPointCount);
        return fPts[n];
    }
    SkDPoint &operator[](int n)
    {
        SkASSERT(n >= 0 && n < kPointCount);
        return fPts[n];
    }

    void align(int endIndex, int ctrlIndex, SkDPoint *dstPt) const;
    double binarySearch(double min, double max, double axisIntercept, SearchAxis xAxis) const;
    double calcPrecision() const;
    SkDCubicPair chopAt(double t) const;
    static void Coefficients(const double *cubic, double *A, double *B, double *C, double *D);
    static int ComplexBreak(const SkPoint pts[4], SkScalar *t);
    int convexHull(char order[kPointCount]) const;

    void debugInit()
    {
        sk_bzero(fPts, sizeof(fPts));
    }

    void debugSet(const SkDPoint *pts);

    void dump() const; // callable from the debugger when the implementation code is linked in
    void dumpID(int id) const;
    void dumpInner() const;
    SkDVector dxdyAtT(double t) const;
    bool endsAreExtremaInXOrY() const;
    static int FindExtrema(const double src[], double tValue[2]);
    int findInflections(double tValues[2]) const;

    static int FindInflections(const SkPoint a[kPointCount], double tValues[2])
    {
        SkDCubic cubic;
        return cubic.set(a).findInflections(tValues);
    }

    int findMaxCurvature(double tValues[]) const;

#ifdef SK_DEBUG
    SkOpGlobalState *globalState() const
    {
        return fDebugGlobalState;
    }
#endif

    bool hullIntersects(const SkDCubic &c2, bool *isLinear) const;
    bool hullIntersects(const SkDConic &c, bool *isLinear) const;
    bool hullIntersects(const SkDQuad &c2, bool *isLinear) const;
    bool hullIntersects(const SkDPoint *pts, int ptCount, bool *isLinear) const;
    bool isLinear(int startIndex, int endIndex) const;
    static int maxIntersections()
    {
        return kMaxIntersections;
    }
    bool monotonicInX() const;
    bool monotonicInY() const;
    void otherPts(int index, const SkDPoint *o1Pts[kPointCount - 1]) const;
    static int pointCount()
    {
        return kPointCount;
    }
    static int pointLast()
    {
        return kPointLast;
    }
    SkDPoint ptAtT(double t) const;
    static int RootsReal(double A, double B, double C, double D, double t[3]);
    static int RootsValidT(const double A, const double B, const double C, double D, double s[3]);

    int searchRoots(double extremes[6], int extrema, double axisIntercept, SearchAxis xAxis, double *validRoots) const;

    bool toFloatPoints(SkPoint *) const;
    /* *
     * Return the number of valid roots (0 < root < 1) for this cubic intersecting the
     * specified horizontal line.
     */
    int horizontalIntersect(double yIntercept, double roots[3]) const;
    /* *
     * Return the number of valid roots (0 < root < 1) for this cubic intersecting the
     * specified vertical line.
     */
    int verticalIntersect(double xIntercept, double roots[3]) const;

    // add debug only global pointer so asserts can be skipped by fuzzers
    const SkDCubic &set(const SkPoint pts[kPointCount] SkDEBUGPARAMS(SkOpGlobalState *state = nullptr))
    {
        fPts[0] = pts[0];
        fPts[1] = pts[1];
        fPts[2] = pts[2];
        fPts[3] = pts[3];
        SkDEBUGCODE(fDebugGlobalState = state);
        return *this;
    }

    SkDCubic subDivide(double t1, double t2) const;
    void subDivide(double t1, double t2, SkDCubic *c) const
    {
        *c = this->subDivide(t1, t2);
    }

    static SkDCubic SubDivide(const SkPoint a[kPointCount], double t1, double t2)
    {
        SkDCubic cubic;
        return cubic.set(a).subDivide(t1, t2);
    }

    void subDivide(const SkDPoint &a, const SkDPoint &d, double t1, double t2, SkDPoint p[2]) const;

    static void SubDivide(const SkPoint pts[kPointCount], const SkDPoint &a, const SkDPoint &d, double t1, double t2,
        SkDPoint p[2])
    {
        SkDCubic cubic;
        cubic.set(pts).subDivide(a, d, t1, t2, p);
    }

    double top(const SkDCubic &dCurve, double startT, double endT, SkDPoint *topPt) const;
    SkDQuad toQuad() const;

    static const int gPrecisionUnit;
    SkDPoint fPts[kPointCount];
    SkDEBUGCODE(SkOpGlobalState *fDebugGlobalState);
};

/* Given the set [0, 1, 2, 3], and two of the four members, compute an XOR mask
   that computes the other two. Note that:

   one ^ two == 3 for (0, 3), (1, 2)
   one ^ two <  3 for (0, 1), (0, 2), (1, 3), (2, 3)
   3 - (one ^ two) is either 0, 1, or 2
   1 >> (3 - (one ^ two)) is either 0 or 1
thus:
   returned == 2 for (0, 3), (1, 2)
   returned == 3 for (0, 1), (0, 2), (1, 3), (2, 3)
given that:
   (0, 3) ^ 2 -> (2, 1)  (1, 2) ^ 2 -> (3, 0)
   (0, 1) ^ 3 -> (3, 2)  (0, 2) ^ 3 -> (3, 1)  (1, 3) ^ 3 -> (2, 0)  (2, 3) ^ 3 -> (1, 0)
*/
inline int other_two(int one, int two)
{
    return 1 >> (3 - (one ^ two)) ^ 3;
}

struct SkDCubicPair {
    SkDCubic first() const
    {
#ifdef SK_DEBUG
        SkDCubic result;
        result.debugSet(&pts[0]);
        return result;
#else
        return (const SkDCubic &)pts[0];
#endif
    }
    SkDCubic second() const
    {
#ifdef SK_DEBUG
        SkDCubic result;
        result.debugSet(&pts[3]);
        return result;
#else
        return (const SkDCubic &)pts[3];
#endif
    }
    SkDPoint pts[7];
};

class SkTCubic : public SkTCurve {
public:
    SkDCubic fCubic;

    SkTCubic() {}

    SkTCubic(const SkDCubic &c) : fCubic(c) {}

    ~SkTCubic() override {}

    const SkDPoint &operator[](int n) const override
    {
        return fCubic[n];
    }
    SkDPoint &operator[](int n) override
    {
        return fCubic[n];
    }

    bool collapsed() const override
    {
        return fCubic.collapsed();
    }
    bool controlsInside() const override
    {
        return fCubic.controlsInside();
    }
    void debugInit() override
    {
        return fCubic.debugInit();
    }
#if DEBUG_T_SECT
    void dumpID(int id) const override
    {
        return fCubic.dumpID(id);
    }
#endif
    SkDVector dxdyAtT(double t) const override
    {
        return fCubic.dxdyAtT(t);
    }
#ifdef SK_DEBUG
    SkOpGlobalState *globalState() const override
    {
        return fCubic.globalState();
    }
#endif
    bool hullIntersects(const SkDQuad &quad, bool *isLinear) const override;
    bool hullIntersects(const SkDConic &conic, bool *isLinear) const override;

    bool hullIntersects(const SkDCubic &cubic, bool *isLinear) const override
    {
        return cubic.hullIntersects(fCubic, isLinear);
    }

    bool hullIntersects(const SkTCurve &curve, bool *isLinear) const override
    {
        return curve.hullIntersects(fCubic, isLinear);
    }

    int intersectRay(SkIntersections *i, const SkDLine &line) const override;
    bool IsConic() const override
    {
        return false;
    }
    SkTCurve *make(SkArenaAlloc &heap) const override
    {
        return heap.make<SkTCubic>();
    }

    int maxIntersections() const override
    {
        return SkDCubic::kMaxIntersections;
    }

    void otherPts(int oddMan, const SkDPoint *endPt[2]) const override
    {
        fCubic.otherPts(oddMan, endPt);
    }

    int pointCount() const override
    {
        return SkDCubic::kPointCount;
    }
    int pointLast() const override
    {
        return SkDCubic::kPointLast;
    }
    SkDPoint ptAtT(double t) const override
    {
        return fCubic.ptAtT(t);
    }
    void setBounds(SkDRect *) const override;

    void subDivide(double t1, double t2, SkTCurve *curve) const override
    {
        ((SkTCubic *)curve)->fCubic = fCubic.subDivide(t1, t2);
    }
};

#endif
